This invention relates, in general, to sensing devices, and more particularly to devices for sensing linear and rotational acceleration.
In navigation or positional tracking systems it is often necessary to monitor and calculate six acceleration values. The first three are linear acceleration, which quantify the rate at which an object is accelerating in the x-, y-, and z-directions. By monitoring the rate at which the object is accelerating in these directions, it is possible to calculate the relative velocity in each of these directions. It is also necessary to sense and monitor the angular or rotational acceleration of an object, which provides the final three acceleration values that are needed in many navigation systems. Rotational acceleration refers to the rate of change in angular velocity or rotational rate of an object about the x-, y-, or z-axis. In aviation systems these three accelerations are often referred to as roll, pitch, and yaw forces, respectively.
Traditional sensing devices are generally divided into two categories: those that sense linear acceleration and those that sense rotational velocity/acceleration. Many of these devices are only capable of sensing either the linear or rotational acceleration along one of the three axes. Thus, to form a tracking system that is capable of monitoring all six of the above mentioned accelerations, it may be necessary to combine several sensing devices into the tracking system. Combining several sensing devices to fulfill the necessary functionality increases the size and manufacturing cost of the tracking system.
By now it should be appreciated that it would be advantageous to increase the functionality of a sensing device so that fewer sensing devices are required by a tracking system to sense linear and rotational acceleration along all three Cartesian axes.